title: Live and ultraviolet-inactivated Lactobacillus rhamnosus GG decrease flagellin-induced interleukin-8 production in Caco-2 cells.
abstract: Probiotics are widely used in the treatment and prevention of gastrointestinal problems. However, in some immune-compromised populations, the administration of live microorganisms may not be appropriate. A potential alternative to live microorganisms is to inactivate them as long as the beneficial function is retained. We hypothesized that UV-inactivated Lactobacillus rhamnosus GG (LGG) could downregulate interleukin-8 (IL-8) production in intestinal epithelial cells stimulated by the pathogenic ligand, flagellin, using similar mechanisms as live LGG. Caco-2 cells were pretreated with live or UV-inactivated LGG at 10(11) colony-forming units/L and stimulated by flagellin at a dose of 500 mug/L. IL-8 production was measured by ELISA, inhibitor of kappaB (IkappaB) and ubiquitinated-IkappaB (Ub-IkappaB) expression by immunoblotting and nuclear factor (NF) kappaB localization by immunofluorescence staining. Flagellin induced a 17-fold increase in IL-8 production compared with control (P < 0.05), whereas pretreatment with either live LGG or UV-inactivated LGG resulted in 66 and 59% decreases, respectively, compared with the flagellin group (P < 0.05). Flagellin-induced NFkappaB nuclear translocation was prevented by both live and UV-inactivated LGG. Flagellin decreased IkappaB, which was reversed by either live or UV-inactivated LGG (P < 0.05). UV-inactivated LGG decreased Ub-IkappaB expression (P < 0.05), although live LGG had no effect. This study supports the concept that UV-inactivated and live LGG are equally effective in decreasing IL-8 production in the intestinal epithelium. Although the mechanism involves different pathways, both alter cytoplasmic IkappaB, thereby inhibiting NFkappaB nuclear translocation.
authors.affiliation: Department of Pediatrics, University of Florida, Gainesville, FL 32610-0296, USA.
authors.forename: Mariela
authors.initials: M
authors.lastname: Lopez
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.forename: Jasmeet
authors.initials: J
authors.lastname: Kataria
authors.forename: Michael
authors.initials: M
authors.lastname: Russell
authors.forename: Josef
authors.initials: J
authors.lastname: Neu
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism; D018938:Caco-2 Cells; D005408:Flagellin / Q000494:pharmacology*; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D016209:Interleukin-8 / Q000096:biosynthesis*; D052201:Lacticaseibacillus rhamnosus / Q000378:metabolism* / Q000528:radiation effects*; D054875:Ubiquitination; D014466:Ultraviolet Rays
chemical_list: D016209:Interleukin-8; D005408:Flagellin; D051550:I-kappa B Kinase